Hey Doug,
First, here is the easy part:
http://boatbuilders.glen-l.com/36964/fi ... mment-1709
Second, As you will see in my blog (choke, choke), I found a Bic Whiteout pen to make a good accurate mark. Then, I took my cheap chinese 3-in-1 plaz and blasted along the line. Worked perfectly, and there was just enough room for a loose fit and filler weld to reinforce the joint. Don't forget to leave limber slots along the keel. I left about a 1/8 X 1/4" tall slot for the drainage. There is plenty of contact surface left to weld to. There is nothing like a fresh tip for these cuts. I bought an extra bag of 100 tip-sets so I would not be tempted to "try and make due" on the cuts. In all, I think I used up a half dozen of them in the 9 frames. And I used another half dozen in the stiffener slots. However, at a Quarter-to-50 cents a set, that is the least of my expenses. Also, remember, I was only cutting 3/16" instead of the plan spec of 1/4". Trust me, it makes a bunch of differences. Now past that step, I am so glad I went with the lighter stock. The design is plenty "healthy" in thickness of stock.
As for the fantail issue, I would have to see a pics and a jpeg of the plan, and have you on the horn with me. You are right though, compounds are harder. I would consider multiple slits if I HAD to do the compound thing, or ivest in a HFT English Wheel. Personally, I would find a reason to do it a different way. There is ALWAYS a good excuse for doing it simpler, even if it means a step or settee on the inside or a built-in swim ladder on the outside. Frenched holes, "designer" fluting, and the list goes on. And when you get depressed looking at the fabing, remember, at least you are not trying to cut and weld wood.

Don't get me wrong. I love wood as much as the next tree-hugger. But there are some things one material does better than another... I have had to do a bit of that on the "G".
I still have not set on a ship name yet. I have some ideas, and even have spoken to a friend who is a world -class song writer for some help. But that will come in time. AAAH! There is an idea!... I can call it the "G_string, My Fat Bottomed Girl" WHooo, ... that was one I think I needed to let pass. I am sure my wife would not like it at all. No reflection on her mind you, just brings back Youtube snippets of redneck yacht-club parties, one wants to forget.
Haven't seen any "at-sea" videos or pics yet of these lit'l darlins. All I have found so far are some dock pics and some on trailers. I often wonder if folks think they will melt if you put them in water and turn stuff on...

If you have any visual media to share, by all means...
Now for the last question, powertrain. Like I have been telling others, yes and no. I think I have settled on a plan for the system. It is a bit involved and requires me to design and build the parts, units, and so forth. No, I am not ready to divuldge that yet. I do however, have a backup plan if I am not able to successfully build what I have envisioned. It sounds like you have yours well in hand. I think I would opt for the diesel Volvo, and then go get a one-lunger yanmar diesel. I have one I got new for like $400. It is electric start and very dependable. Weight is not bad either. It is an L70AE. Placarded as 4.4 Kw continous and 5.0 on the short term. It has a throttle, compression relief, tank and is air cooled. I am sure there are similar out there that are water cooled though.
Gotta run, business calls...
Better, faster, cheaper. Only ever found 2 of the 3! (But still lookin.)
So many boats, ...so little time.